The patent literature has fully disclosed the preparation of polyimide oligomers and precursors by reaction of aromatic compounds, such as pyromellitic acid and 3,3' ,4,4' -benzophenonetetracarboxylic acid, lower alkyl esters thereof, of the corresponding dianhydrides, with aromatic diamines. The fully cured polyimide compounds are relatively insoluble and intractable materials. When they are used as laminating resins, adhesives, etc., they are applied in the form of the polyamic acid or ester precursor and then cured. This cure step produces water or alcohol as byproduct, resulting in the formation of undesirable voids in the final composite assembly.